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Expansion valve and method for controlling it

a technology of expansion valve and control method, which is applied in the direction of non-reversible cycle compression machines, functional valve types, lighting and heating apparatus, etc., can solve the problems of complex structure, high production cost and assembly cost of expansion valve, etc., and achieve the effect of reducing the number of connection points, accurate setting of expansion valve, and simplifying the connection poin

Inactive Publication Date: 2009-02-10
OTTO EGELHOF GMBH & CO KG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The invention proposes an expansion valve and a method for controlling it that is cost-effective and easy to operate. The valve is controlled by a pressure difference between the entry and exit pressures of the refrigerant cycle, which results in an optimal high pressure upstream of the valve. The method allows for a continuous control of the valve opening as a function of the pressure difference, ensuring an optimal mass flow of refrigerant and energy efficiency. The invention also provides an expansion valve that allows for fine tuning in the pressure difference range to achieve the desired high pressure. The invention achieves an optimal COP (coefficient of performance) in both the sub-critical and super-critical ranges.

Problems solved by technology

However, this solution has the drawback of requiring a complex structure.
Actuation of the solenoid valve requires the use of a pressure and temperature sensor or a control box with software in the control circuit, making this expansion valve expensive to produce and assemble.

Method used

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  • Expansion valve and method for controlling it
  • Expansion valve and method for controlling it
  • Expansion valve and method for controlling it

Examples

Experimental program
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Embodiment Construction

[0042]FIG. 1 illustrates a refrigerant cycle 11 which is preferably operated with CO2 as refrigerant. A compressor 12 feeds the compressed refrigerant to an external heat exchanger 14 on the high pressure side. The external heat exchanger 14 is connected to atmosphere and dissipates heat to the outside. An internal heat exchanger 15, which feeds the refrigerant to an expansion valve 16 via a feed line 17, is connected downstream of the external heat exchanger. Upstream of the expansion valve 16 on the high-pressure side is an entry pressure which may, for example, be 120 bar in the summer and up to 80 bar in the winter. The refrigerant flows through the expansion valve 16 and reaches the low-pressure side. On the exit side, the expansion valve 16 provides pressures of between 35 and 45 bar. The refrigerant which has been cooled through the pressure expansion passes via a discharge line 18 into the internal heat exchanger 21 and withdraws heat from the surroundings, with the result t...

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Abstract

The invention relates to an expansion valve and to a method for controlling an expansion valve, in which the opening and closing movement of the valve-closure member is set as a function of the pressure difference which is present in a feed opening on the high pressure side and in a discharge opening.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The invention relates to an expansion valve and to a method for controlling it, in particular in the form of vehicle air-conditioning systems which are operated with CO2 as refrigerant and have a valve housing with a feed opening and a discharge opening, and with a valve member which can be displaced out of a valve seat of a through-flow opening arranged between the feed opening and discharge opening to allow the refrigerant to flow through.[0003]2. Description of Related Art[0004]Carbon dioxide (CO2) is the preferred refrigerant for refrigerant cycles of air-conditioning systems of motor vehicles of the future, since this substance is very safe in the event of accidents, on account of being non-combustible, and furthermore it is not considered an environmental pollutant. CO2 refrigeration cycles, unlike R134a refrigeration cycles, are also operated in the supercritical range.[0005]An expansion valve which is used in re...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): F25B41/04F16K17/26G05D23/02F16K31/68F25B1/00F25B9/00F25B40/00F25B41/06
CPCF25B9/008F25B41/062F25B2341/063F25B2500/01Y10T137/7779F25B41/33
Inventor ROBIN, JEAN-JACQUESWINTERSTEIN, RALFKUMMEROW, KLAUS
Owner OTTO EGELHOF GMBH & CO KG